Green manure, rock phosphate and gypsum for cassava crop in clayey texture, Dusky Red Latosol

Abstract

In one clayey texture, Dusky Red Latosol, 0, 1000, 2000 and 3000 kg/ha of rock phosphate (apatita-de-araxá) and 0, 500, 1000 kg/ha of gypsum were applied on 09.05.86. Crotalaria juncea was planted without fertilizers on 10.20.86 and incorporated into the soil by a disk plow at beginning pod stage on 02.15.89. Sixty days after green manure (Crotalaria) incorporation the subplot soil samples were chemically analyzed. Cassava (Manihot esculenta), IAC 12829 cultivar, was planted on 11.15.87 and harvested on May 1989. The experimental design was a completely randomized block in split plot arrangement, with rock phosphate and gypsum treatments in the plots and green manure in the subplot. Leaf surface and petiole nutrient contents were determined, and also were evaluated the roots and shoot yield, harvest index, plants height. Green manure, gypsum and rock phosphate affected the yield and yield components, and also the chemical soil characteristic. The results indicated that these low cost soil amendments and green manure can be used for good cassava yields.